Capacity management in deduplication storage systems

ABSTRACT

A deduplication storage capacity is estimated as a function of an expected deduplication ratio, the expected deduplication ratio being a combined average of a current deduplication ratio and a configured deduplication ratio, the current deduplication ratio depending on the data currently stored in the deduplication storage, and the configured deduplication ratio being an estimate made at a configuration stage of the deduplication computing storage environment.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to computers, and moreparticularly to apparatus and computer program product embodiments forcapacity management in deduplication storage systems.

2. Description of the Related Art

Data deduplication refers to the reduction and/or elimination ofredundant data. In a data deduplication process, duplicate copies ofdata are reduced or eliminated, leaving a minimal amount of redundantcopies, or a single copy of the data, respectively. Using deduplicationprocesses provides a variety of benefits, such as reduction of requiredstorage capacity and reduction of network bandwidth. Due to these andother benefits, deduplication has emerged in recent years as a highlyimportant technological field in computing storage systems. Challengesto providing deduplication functionality include aspects such asefficiently finding duplicated data patterns in typically large storagerepositories, and storing the data patterns in a deduplicatedstorage-efficient form.

SUMMARY OF THE INVENTION

A significant challenge in deduplication storage systems is therequirement to compute and report their capacity. Although reportingcapacity in terms of physical storage is possible, in a user'sperspective this may not be sufficient to accurately describe the actualsystem capacity. The reason for this is that the actual system capacity,in the user's perspective, depends, in addition to physical storage,also on the deduplication ratio. For example, for a storage system whosephysical capacity is 1 terabyte, where the deduplication ratio of thedata streamed into the system is 1:5 (i.e. only ⅕ of the data is uniqueand the rest is duplicated data), the actual system capacity in theuser's perspective is 5 terabytes.

The challenge in accurate capacity reporting stems from the fact thatthe deduplication ratio depends both on the specific data stored withinthe deduplication storage system at any given time, and on the data thatis yet to be streamed into the storage system. The deduplication ratiois therefore dynamic over time.

Moreover, it may be required to partition the total capacity of adeduplication storage system into portions. For example, a user mayrequire to partition the total storage capacity into portionscorresponding to different data types or data sources. In doing so it isgenerally required that the storage capacity of the defined portionscorresponds and fluctuates with the effects of the changingdeduplication ratio on the system capacity. A mechanism that allows fordefinition of such partitioning of a deduplication storage, and enablesthe partitioning to fluctuate and change in a sensible manner inaccordance with the effects of the changing deduplication ratio isrequired.

Existing approaches for partitioning of deduplication storage systemsare mainly based on defining portions of the physical storage. With suchapproaches the portions defined are generally physical entities, ratherthan logical entities, thus frequently reducing the flexibility by whichuser data associated with a portion is stored in the physical storage.When user data is streamed into a deduplication storage system, parts ofthe data that are not found in the system are written to the physicalstorage, and parts that are found are recorded generally as references.When user data is streamed into a defined portion of the physicalstorage, the data written to the physical storage can be associated withthe consumed size of that portion. However, there is difficulty inassociating the references with any of the physical portions. Ifreferences are considered in the consumed storage calculation, then thecalculations of both the consumed storage and the capacity of thestorage are no longer physical. On the other hand if references aredisregarded in the consumed storage calculation, then storage capacitymay be lost when user data is deleted. In addition, with physicalpartitioning, when adding or deleting user data from the storage system,identifying the other portions affected by these operations may entail asystem scan, which is expensive in runtime. Essentially, definingphysical partitioning practically disregards the effects of thededuplication ratio on the partitioning as well as on the entire storagesystem, while these effects are highly significant in enabling coherentand understandable behavior of the partitioning.

In view of the foregoing, a need exists for a mechanism for providingeffective capacity management that serves to address the challengesdescribed previously. Accordingly, various embodiments for capacitymanagement in a deduplication computing storage environment by aprocessor device are provided. In one embodiment, by way of exampleonly, a deduplication storage capacity is estimated as a function of anexpected deduplication ratio, the expected deduplication ratio being acombined average of a current deduplication ratio and a configureddeduplication ratio, the current deduplication ratio depending on thedata currently stored in the deduplication storage, and the configureddeduplication ratio being an estimate made at a configuration stage ofthe deduplication computing storage environment.

In addition to the foregoing exemplary method embodiment, otherexemplary system and computer product embodiments are provided andsupply related advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readilyunderstood, a more particular description of the invention brieflydescribed above will be rendered by reference to specific embodimentsthat are illustrated in the appended drawings. Understanding that thesedrawings depict embodiments of the invention and are not therefore to beconsidered to be limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings, in which:

FIG. 1 illustrates an exemplary computing environment in which aspectsof the present invention may be implemented;

FIG. 2 illustrates an exemplary method for capacity management in adeduplication storage system of a computing environment; and

FIG. 3 illustrates an exemplary portion of a deduplication system asillustrated in FIG. 1, previously, including a processor device.

DETAILED DESCRIPTION OF THE DRAWINGS

Throughout the following description and claimed subject matter, aphysical capacity of a deduplication storage system may be intended torefer to the total physical capacity available for storing user data. Anominal capacity of a deduplication storage system may be intended torefer to the product of the physical capacity multiplied by the expecteddeduplication ratio (which will be defined in the following).

One aspect of the illustrated embodiments, following, concerns computingand reporting the capacity of a deduplication storage system based onnominal sizing (rather than physical sizing). This applies to both theaspects of storage capacity and the consumed storage. This also appliesto the system as a whole, as well as to its user-defined portions.

In one aspect of the illustrated embodiments, the capacity of adeduplication storage system is computed based on an expecteddeduplication ratio. This ratio is computed based on a currentdeduplication ratio, which depends on the data currently stored in thesystem, and on a configured deduplication ratio, which is based on userestimation and is assigned by the user upon configuration. Both of thelatter ratios may be specified and computed per data type defined by theuser, thus producing an expected deduplication ratio per data type.

The current and the configured deduplication ratios are averaged, toproduce the expected deduplication ratio, according to weights, wherethe weight of the current deduplication ratio is higher relative to thatof the configured deduplication ratio, as the system is more mature interms of the data it has processed (more details on that in thefollowing). The consumed size of the storage system is reported, similarto the system capacity, in nominal terms, as the difference between thenominal size of the data streamed into the system and the size of thedata deleted from the system.

In an additional aspect of the illustrated embodiments, the totalcapacity of a deduplication storage system may be partitioned intostorage units (SUs), which are logical units sharing all the physicalstorage. Each SU is assigned by the user with a proportion of thecomputed nominal size of the storage system. Computing capacity valuesof the SUs includes computing the current capacity of the storagesystem, and then computing the current capacities of the SUs, based ontheir assigned proportions. The consumed storage size of each SU iscomputed as the difference between the nominal size of the data streamedinto that SU and the size of the data deleted from that SU.

Computing the capacity of the storage system and its SUs using themechanisms of the illustrated embodiments ensures that the computed andreported total capacity of the storage system, total capacity of itsSUs, as well as the capacity of each individual SU, all correspond andfluctuate in accordance with the effects of the expected deduplicationratio on the capacity of the storage system. Specifically, if thenominal capacity of the storage system increases, based on an increasein the expected deduplication ratio, then the capacities of the storagesystem and its SUs increase accordingly.

Turning now to FIG. 1, exemplary architecture 10 of deduplicationsystems and related components in a computing storage environment, inwhich various aspects of the illustrated embodiments may be implemented,is depicted. Architecture 10 provides storage services to several backuphosts 26. Deduplicated data replication is provided between variousdeduplication system groups 12, 14, 16, and 18 as indicated by dashedlines 22 and 24. Each of groups 12, 14, 16, and 18 include one or morehosts 26, which are connected to a deduplication system 30 vianetworking components such as a switch 28 as indicated. Deduplicationsystems 30 are interconnected via networking components such as a router32, which provides internetwork connectivity between groups 12, 14, 16,and 18. A network 20 connects such deduplication systems 30 and routers32. Network 20 may, in one embodiment, include a wide area network(WAN). In other embodiments, network 20 may include local area networks(LANs), storage area networks (SANs), and other network topologies knownto the skilled artisan. While routers 32 and switches 28 are shown, theskilled artisan will also appreciate that additional and/or substitutenetworking components are contemplated.

In one embodiment, switch 28 is compliant with a fibre channel networkprotocol, making the switch 28 and interconnected components capable ofexecuting commands such as small computer systems interface (SCSI)commands. Such commands may be executed for a variety of storagedevices, again as the skilled artisan will appreciate, such as diskdrives, tape devices, solid state devices (SSDs), and the like. Whilethe architecture 10 provides one example of components that may beutilized to implement various facets of the present invention andclaimed subject matter, the skilled artisan will appreciate that othersuch architectures are contemplated.

In one aspect of the illustrated embodiments, and as previouslymentioned, computing and reporting of the capacity of a deduplicationstorage system is based on nominal sizing (rather than physical sizing).This applies to both the aspects of storage capacity and the consumedstorage. This also applies to the system as a whole as well as to itsuser defined portions.

Again, as stated previously, the capacity of a deduplication storagesystem may, in one aspect of the illustrated embodiments, be computedbased on a formula taking into account the configured deduplicationratio assigned for the system upon configuration based on userestimation, and the current deduplication ratio computed based on thedata currently stored in the system. Both ratios may be specified orcomputed per data type defined by the user.

In one aspect of the illustrated embodiments, the following formulae maybe implemented:System storage capacity=(physical storage capacity−physical storageconsumed)×expected deduplication ratio+nominal size of the datacurrently stored in the system.  [E1]Expected deduplication ratio=Wc×configured deduplicationratio+Wr×current deduplication ratio, where Wc+Wr=1.  [E2]Current deduplication ratio=nominal size of the data currently stored inthe system/physical storage consumed.  [E3]Wr=MAX(physical consumed storage/physical capacity, MIN(1, amount ofdata already streamed into the system/(physical storagecapacity×configured deduplication ratio)))  [E4]

The exemplary formula [E1] for system storage capacity includes twosections. The first section expresses the nominal capacity of thephysical storage still unused (where the deduplication ratio isexpected). The second section expresses the nominal capacity of thestorage already consumed (where the deduplication ratio is alreadyknown).

The weights Wc and Wr in [E2] are defined to depend on the maturity ofthe system in terms of the data it has processed. Namely, as the systemis more mature the weight of the current deduplication ratio increasesrelative to that of the configured deduplication ratio. In one aspect ofthe illustrated embodiments, the maturity of the system is expressedbased on the physical consumed storage ratio of the system and on theamount of data already streamed into the system, using the formula [E4].Note that although the physical consumed storage ratio may be small, theamount of data already streamed into the system may be large, indicatinga mature repository. The nominal system capacity may be used based onthe configured deduplication ratio, as an indication of the data sizethat the user generally intends to store in the system at steady state.

An alternative option of the illustrated embodiments for computing theexpected deduplication ratio is averaging the values of the currentdeduplication ratio, sampling each predefined time interval, where theaverage is computed over the set of recent samples, and the size of thisset is predefined. The weights may be higher for more recent samples. Inone exemplary embodiment the predefined time interval is one hour, andthe size of the recent samples set is 600.

The consumed size of the storage system may be reported, similar to thesystem capacity, in nominal terms. The nominal size of the data streamedinto the system may be tracked, as well as the size of the data deletedfrom the system. Their difference, at any point in time, is the nominalconsumed size in the system.

In one aspect of the illustrated embodiments, the total capacity of adeduplication storage system may be partitioned into storage units(SUs). In an exemplary deduplication storage system each storage unit isa logical unit. Further, all storage units share all the physicalstorage, and are striped across the physical storage. Each SU isassigned by the user with a proportion of the computed nominal size ofthe storage system. The total proportions of the SUs may equal or belower or higher than 100%.

In one aspect of the illustrated embodiments, capacity values of thestorage system and the SUs are computed only upon request to bereported, either externally or internally. Computing capacity values ofthe SUs includes computing the current capacity of the storage system,and then computing the current capacities of the SUs, based on theirassigned proportions. Specifically, the formula for computing thecapacity of a specific SU is the following:SU capacity=MAX(System storage capacity×SU assigned proportion, SUconsumed size), where system storage capacity is computed according to[E1], and the SU consumed size is computed as the difference between thenominal size of the data streamed into that SU and the size of the datadeleted from that SU.  [E5]

Computing the SUs' capacities using the mechanisms of the illustratedembodiments ensures that the total capacity of the SUs, as well as thecapacity of each individual SU, correspond and fluctuate in accordancewith the total capacity of the storage system as a function of thechanges in the expected deduplication ratio. Specifically, if thenominal capacity of the storage system increases, based on an increasein the value of the expected deduplication ratio, then the totalcapacity of the SUs, as well as their individual capacities, increaseaccordingly.

Using [E5] for SU capacity may result in the total SUs capacity beinglarger than the total storage system capacity. This may be permissiblein some storage systems, and may be impermissible in other storagesystems. The following scenarios may result in the total SUs capacitybeing larger than the total storage system capacity. The first scenariois a decrease in the expected deduplication ratio, where some SUs haveconsumed storage causing them to overflow their updated capacity, andthe second scenario is where the consumed storage of SUs is allowed tobe larger than their capacity.

For storage systems where the total SUs capacity can not be larger thanthe total storage system capacity, the SUs capacity is computed usingthe following method. For SUs whose consumed size exceeds theirproportional capacity, which is computed as the system storage capacitymultiplied by their assigned proportion, their capacity is computedaccording to [E5], namely their capacity is set to be equal to theirconsumed size. Throughout the following description, the type of theseSUs is denoted as exceeding SUs. For all other SUs, whose type isdenoted as non-exceeding SUs, their capacity is computed using thefollowing formulae:SU capacity=(System storage capacity−total capacity of the exceedingSUs)×SU updated proportion.  [E6]SU updated proportion=SU assigned proportion/total sum of proportions ofthe non-exceeding SUs.  [E7]

Note that the above computation is iterative. The reason is that whenthe storage system capacity is reduced, e.g. due to a reduction in theexpected deduplication ratio, SUs which are initially part of the nonexceeding set, may become part of the exceeding set when applying theirupdated (and reduced) capacity. Therefore, the above computation isiterated until all SUs whose capacity was reduced in the currentiteration (i.e. all SUs which were classified as non exceeded) remain inthe non-exceeding set.

Turning now to FIG. 2, a flow chart illustration of an exemplary method50 for computing various capacities of the SUs in a deduplicationstorage system is depicted. In one embodiment, method 50 may beimplemented using deduplication system 30 (FIG. 1) components, orvarious other processing, networking, and storage components incomputing environments. As one skilled in the art will appreciate,various steps in the method 50 may be implemented in differing ways tosuit a particular application. In addition, the described method may beimplemented by various means, such as hardware, software, firmware, or acombination thereof operational on or otherwise associated with thecomputing environment. For example, the method 50 may be implemented,partially or wholly, as a computer program product including acomputer-readable storage medium having computer-readable program codeportions stored therein. The computer-readable storage medium mayinclude disk drives, flash memory, digital versatile disks (DVDs),compact disks (CDs), and other types of storage mediums as has beenpreviously described.

Method 50 begins (step 52), by considering a first SU (step 54). Foreach SU considered, the SU capacity is set to be the MAX (System storagecapacity×SU assigned proportion, SU consumed size) (step 56). If (SUconsumed size<=System storage capacity×SU assigned proportion) (step 58)then the SU is assigned into the non-exceeding set (step 60). Else theSU is assigned into the exceeding set (step 62). If an additional SU,which was not yet processed, exists (step 64), the method 50 returns tostep 56 for additional calculations.

If the exceeding set is not empty (step 66), the total capacity of theSUs in the exceeding set is computed (step 68), the total sum ofproportions of the SUs in the non exceeding set is computed (step 70),and the iteration flag is turned off (step 72).

The first SU in the non-exceeding set is considered (step 74). For eachSU in the non exceeding set, the SU updated proportion is computed asequaling the SU assigned proportion/total sum of proportions of the nonexceeding SUs (step 76). The SU capacity is computed as equaling (Systemstorage capacity−total capacity of the exceeding SUs)×SU updatedproportion (step 78). If (SU consumed size>SU capacity) (step 80) thenthe SU capacity is set to be the SU consumed size, the SU is moved fromthe non exceeding set into the exceeding set, and the iteration flag isturned on (step 82). If an additional SU in the non-exceeding set, whichwas not yet processed, exists (step 84), the method returns to step 76for additional processing as shown. Turning to step 86, if the iterationflag is turned on, then the method 50 iterates back to step 68 as shown.Otherwise, the method 50 then ends (step 88).

Turning now to FIG. 3, an exemplary portion 150 of a deduplicationsystem 30 as also seen in FIG. 1, previously, is illustrated. Portion150 of deduplication 30 is operable in a computer environment as aportion thereof, in which mechanisms of the following illustratedembodiments may be implemented. It should be appreciated, however, thatFIG. 3 is only exemplary and is not intended to state or imply anylimitation as to the particular architectures in which the exemplaryaspects of the various embodiments may be implemented. Manymodifications to the architecture depicted in FIG. 3 may be made withoutdeparting from the scope and spirit of the following description andclaimed subject matter.

Deduplication system 30 includes a processor 152 and a memory 153, suchas random access memory (RAM). The deduplication system 30 may beoperatively coupled to several components not illustrated for purposesof convenience, including a display, which presents images such aswindows to the user on a graphical user interface, a keyboard, mouse,printer, and the like. Of course, those skilled in the art willrecognize that any combination of the above components, or any number ofdifferent components, peripherals, and other devices, may be used withthe deduplication system 30.

In the illustrated embodiment, the deduplication system 30 operatesunder control of an operating system (OS) 154 (e.g. z/OS, OS/2, LINUX,UNIX, WINDOWS, MAC OS) stored in the memory 153, and interfaces with theuser to accept inputs and commands and to present results. In oneembodiment of the present invention, the OS 154 facilitates capacitymanagement mechanisms according to the present invention. To this end,OS 154 includes a deduplication module 164 which may be adapted forcarrying out various processes and mechanisms in the exemplary methoddescribed previously.

The deduplication system 30 may implement a compiler 158 that allows anapplication program 156 written in a programming language such as COBOL,PL/1, C, C++, JAVA, ADA, BASIC, VISUAL BASIC or any other programminglanguage to be translated into code that is readable by the processor152. After completion, the application program 156 accesses andmanipulates data stored in the memory 153 of the system 30 using therelationships and logic that was generated using the compiler 158.

To further implement and execute mechanisms and processes according tothe present invention, OS 154, in conjunction with memory 153, processor152, application program 56, and other computer processing, networking,and storage components, may implement and/or maintain deduplicationfiles 162. As the skilled artisan will appreciate, the mechanisms ofdeduplication files 162 as presently illustrated may be implemented invarious forms and architectures. Accordingly, the illustration ofdeduplication files 162 in the present figure is again intended todemonstrate logical relationships between possible computing componentsin the deduplication system 30, and not to imply a specific physicalstructure or relationship.

In one embodiment, instructions implementing the operating system 154,the application program 156, and the 158, as well as the deduplicationfiles 162 and the dynamic metadata files 160 are tangibly embodied in acomputer-readable medium, which may include one or more fixed orremovable data storage devices, such as a zip drive, disk, hard drive,DVD/CD-ROM, digital tape, SSDs, etc. Further, the operating system 154and the application program 156 comprise instructions which, when readand executed by the system 30, cause the system 30 to perform the stepsnecessary to implement and/or use the present invention. Applicationprogram 156 and/or operating system 154 instructions may also betangibly embodied in the memory 53 and/or transmitted through oraccessed by network 20 via various components (e.g., router 32, FIG. 1).As such, the terms “article of manufacture,” “program storage device”and “computer program product” as may be used herein are intended toencompass a computer program accessible and/or operable from anycomputer readable device or media.

Embodiments of the present invention may include one or more associatedsoftware application programs 156 that include, for example, functionsfor managing a distributed computer system comprising a network ofcomputing devices, such as a storage area network (SAN). Accordingly,processor 152 may comprise one or more storage management processors(SMP). The application program 156 may operate within a single computerand/or deduplication system 30 or as part of a distributed computersystem comprising a network of computing devices. The network mayencompass one or more computers connected via a local area networkand/or Internet connection (which may be public or secure, e.g. througha virtual private network (VPN) connection), or via a fibre channel SANor other known network types as will be understood by those skilled inthe art. (Note that a fibre channel SAN is typically used only forcomputers to communicate with storage systems, and not with each other.)

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wired, optical fiber cable, RF, etc., or any suitable combination of theforegoing. Computer program code for carrying out operations for aspectsof the present invention may be written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Java, Smalltalk, C++ or the like and conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The program code may execute entirelyon the user's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer, other programmable data processing apparatus, orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the above figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

While one or more embodiments of the present invention have beenillustrated in detail, the skilled artisan will appreciate thatmodifications and adaptations to those embodiments may be made withoutdeparting from the scope of the present invention as set forth in thefollowing claims.

What is claimed is:
 1. A system for capacity management in a deduplication computing storage environment, comprising: at least one processor device, operable in the deduplication computing storage environment, wherein the at least one processor device is adapted for: estimating a deduplication storage capacity as a function of an expected deduplication ratio, the expected deduplication ratio being an aggregation of a current deduplication ratio and a configured deduplication ratio, the current deduplication ratio depending on data currently stored in deduplication storage, the configured deduplication ratio being an estimate made at a configuration stage of the deduplication computing storage environment, wherein the at least one processor device is further adapted for estimating the deduplication storage capacity includes estimating Scapacity as a function of Pcapacity, Pconsumed, Rexpected, and Dnominal, where Scapacity is the deduplication storage capacity, Pcapacity is a physical storage capacity of the deduplication storage environment, Pconsumed is an amount of physical storage consumed in the deduplication storage environment, Rexpected is the expected deduplication ratio, and Dnominal is a nominal size of data currently stored in the deduplication storage environment.
 2. The system of claim 1, wherein the at least one processor device is further adapted for calculating the expected deduplication ratio as a function of Wc, Rconfigured, WR, and Rcurrent, where Wc and WR are predefined weights dependent on a system maturity, Rconfigured is the configured deduplication ratio, and Rcurrent is the current deduplication ratio.
 3. The system of claim 2, wherein the at least one processor device is further adapted for calculating the current deduplication ratio as a function of D_(nominal), and P_(consumed), where D_(nominal) is the nominal size of data currently stored in the deduplication storage environment, and P_(consumed) is the amount of physical storage consumed in the deduplication storage environment.
 4. The system of claim 1, wherein the at least one processor device is further adapted for partitioning the deduplication storage capacity into a plurality of storage units (SUs), each of the plurality of SUs being a logical unit, and all SUs sharing a physical storage.
 5. The system of claim 4, wherein a selected one of the plurality of SUs is assigned with a proportion of the deduplication storage capacity, the total proportions of the plurality of SUs one of equal, lower, and higher than 100%.
 6. The system of claim 5, wherein the at least one processor device is further adapted for, if for the one of the plurality of SUs a consumed size exceeds a proportional capacity, which is computed as the deduplication storage capacity multiplied by an assigned proportion, calculating a capacity as a function of S_(capacity), SU_(assigned), and SU_(consumed), where S_(capacity) is the deduplication storage capacity, SU_(assigned) is an assigned storage proportion for the one SU, and SU_(consumed) is a difference between a nominal size of data streamed into the one SU and a data size deleted from the one SU.
 7. The system of claim 6, wherein the at least one processor device is further adapted for, if the consumed size does not exceed the proportional capacity, calculating the capacity as a function of S_(capacity), T_(capacity), and SU_(updated), where S_(capacity) is the deduplication storage capacity, T_(capacity) is a total capacity of all exceeding SU of the plurality of SUs, and SU_(updated) is an updated proportion defined by SU_(assigned), and S_(non-exceeding), where SU_(assigned) is the assigned storage proportion for the one SU and S_(non-exceeding) is a total sum of proportions of all non-exceeding SU of the plurality of SUs. 